Cox was known as a segregationist and referred to blacks as "baboons" from the bench.[1] When the United States Justice Department sued to block Mississippi's prosecution of John Hardy, a black resident who was beaten after he attempted to register to vote, Judge Cox denied the Department's motion for a temporary restraining order.[1] The Fifth Circuit Court of Appeals reversed Judge Cox's decision,[2] and the Supreme Court denied review of the appellate decision.[3]

Judge Cox's most famous case was United States v. Price (1965), the federal government's effort to prosecute those who allegedly killed three Mississippi civil rights workers. Cox initially dismissed the indictments on all but two of those charged on the grounds that they were not government officials and therefore could not be charged with acting "under color of law." On appeal, Cox's action was reversed by the U.S. Supreme Court in 1966; Cox then presided over a trial that convicted some of those charged. He issued three to ten year sentences for the convictions of first- and second-degree murder. Cox said of his sentences, "They killed one nigger, one Jew, and a white man. I gave them all what I thought they deserved."[4]

He served as chief judge from 1962 to 1971, and assumed senior status on October 4, 1982. Cox served in that capacity until his death in 1988 in Jackson, Mississippi.